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United States Patent | 5,578,555 |
Duperray | November 26, 1996 |
A method of monitoring the fabrication of a superconductive material having a high critical temperature is wherein: the starting material is a mixture of powders of precursors for said material having stoichiometric proportions appropriate for the desired superconductive phase; the said mixture is agglomerated to form a tubular or a cylindrical piece; the agglomerated piece is placed in a controlled-atmosphere oven for synthesizing said superconductive phase; the conductivity of said piece is measured continuously; the temperature at which conductivity begins to decrease is exceeded and then the temperature is returned to a value where conductivity begins to increase; and the temperature of the oven is permanently adjusted so that said conductivity does not decrease.
Inventors: | Duperray; G erard (La Norville, FR) |
Assignee: | Alcatel Alsthom Compagnie Generale d'Electricite (Paris Cedex, FR) |
Appl. No.: | 348063 |
Filed: | November 23, 1994 |
Sep 30, 1991[FR] | 91 11990 |
Current U.S. Class: | 505/450; 505/310; 505/501; 505/725; 505/782 |
Intern'l Class: | H01B 012/00; C04B 035/622; C04B 035/653 |
Field of Search: | 252/518,521 505/100,725,782,310,501,726,450 |
5189011 | Feb., 1993 | Itozaki et al. | 505/1. |
Chemical Abstracts, vol. 112, No. 14, Apr. 2, 1990, Columbus, Ohio, US; abstract No. 130159A, V. Boffa et al.: `Effects Of Sintering Conditions On The Transport Properties Of Yttrium Barium Copper Oxide Pellets`. Journal Of Materials Science, vol. 25, No. 11, Nov. 1990, London, Great Britain, pp. 4852-4855; D. Bahadur et al.: "Effect Of Optimum Thermal Treatment On BiSrCaCu.sub.2 O.sub.y Experimental Procedure". Japanese Journal of Applied Physics, vol. 28, No. 5, May 1989, Tokyo, Japan, pp. 772-774; S. Kobayashi et al.: "The Effect Of Sintering Conditions On the Formation Of The High-Tc Phase In The Bi-Sr-Ca-Cu-O System". Journal Of Vacuum Science & Technology, vol. 9, No. 3, Jun. 1991, US, pp. 394-400; L. M. Chen et al: "Studies Of The Behavior Of The `123` Superconductor System During Changes In Atmospheric Conditions". Ratto "Monitoring Sintering/densification and Crystallization/grain-growth . . ." Jap. Jnl. Appl Phys. v. 29(2) Feb. 1990 pp. 244-251. Inoue "Superconductive Transition at 120K in a Ti-Bi-Sr-Ca-Cu-O . . ." Jap Jnl Appl Phys. v. 28(7) Jul. 1989 pp. L1167-L1170. Rong-ying "The Specific heat of the single-phase (Bi,Pb).sub.2 Sr.sub.2 Ca.sub.2 Cu.sub.3 O.sub.10 . . ." Physica C v. 158 1989 pp. 255-257 no month available. Che et al. "Composition & Superconductivity in Bi-Sr-Ca-Cu-O . . ." Journ of Mat. Science vol. 24, May 1989 pp. 1725-1728. |